Method for controlling radiation from a source

Abstract

Electromagnetic radiation is directed at reactive materials in a reaction chamber comprising side-by-side volumes, and the probability of the electromagnetic radiation interacting with the reactants is increased by using multiple reflections, the reaction chamber comprising multiple pairs of opposing reflective surfaces, where at least 50% of the reflections from the reflective surfaces are specular, more preferably at least 80% or 90%, and one or both of each pair of reflective surfaces are concave mirrors, and the pairs are configured side-by-side such that radiation escaping through a side of one volume enters a side of the next adjacent volume.

Description

[Technical field]

[0001] The present invention relates to a method for controlling or directing radiation from a source and provides several novel aspects.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS This disclosure is related to the disclosures relating to spectrometers disclosed in U.S. Pat. No. 10,585,044, issued on March 10, 2020, by the present inventor and entitled High Efficiency Multiplexing, hereinafter the "HEMS Patent," the disclosures of which are incorporated herein by reference.

[0003] This disclosure relates to the inventor's disclosures of multi-pass photochemical systems, hereinafter the "MPS Patents," the subject matter of which is described in U.S. patent application Ser. Nos. 17 / 378,144, 17 / 378,154, 17 / 378,158, 17 / 378,163, 17 / 378,171, 17 / 378,175, and 17 / 378,186, all filed on July 16, 2021, and published in PCT application PCT / CA2021 / 050976, filed on July 15, 2021, and published as WO 2022 / 022472 on January 20, 2022, the disclosures of which are incorporated herein by reference. [Background technology]

[0004] In many applications, it is desirable to maximize the radiant power passing through the aperture. In spectroscopic applications, the signal-to-noise ratio is proportional to the square root of the radiant power passing through the limiting aperture below a threshold angular divergence. In germicidal and photoreactive applications, the germicidal rate or reaction rate is proportional to the square root of the radiant power passing through the limiting aperture below a threshold angular divergence. It is therefore desirable to have a way to increase the flux intensity passing through the limiting aperture.

[0005] The radiant power of an optical source, whether emitted, scattered, or reflected, is proportional to its surface area. It is therefore desirable to maximize the surface area from which radiant power can pass through the limiting aperture. It is well established in the art to position the optical source at a location centered on the focal point of the optical assembly, and to image the optical source on and through the aperture. The aperture can then become the source for a second optical assembly that collimates the radiation that has passed through the aperture. In the prior art, there are three main limitations on the amount of radiant power that can pass through an aperture. The first limitation is the solid angle of the radiation source that is allowed by the optical assembly. That is, power emitted in some directions is not collected by the optical assembly. The second limitation is that some of the radiation collected by the optical assembly is not imaged and directed through the aperture. The third limitation is that a portion of the radiation collected by the optical assembly is absorbed. Absorption consists of two parts: radiation absorbed by the optical elements in the optical assembly, and radiation directed by the optical elements to the radiation source where absorption occurs. For example, in prior art parabolic reflector systems, the radiation source is at the center of the focal point (or focal plane) of the parabolic reflector, and radiation emitted towards the apex of the parabolic surface is reflected back towards the focal point where the radiation is absorbed with high efficiency. For example, if the radiation source is a gas discharge lamp, a first radiation flux is emitted by atoms transitioning from an excited state to a ground state (or a lower excited state). The radiation flux reflected back towards the focal point may then excite another atom of the same type from the ground state to an excited state. In a system in thermodynamic equilibrium, the number of particles in the ground state is greater than the number of particles in the excited state, and as a result, absorption is more likely than emission. The energy of the absorbed photon may be re-emitted as a second photon, or the photon energy may be transferred to heat, for example by atomic collisions. That is, more energy is absorbed than is re-emitted. Summary of the Invention

[0006] The arrangements described herein provide several aspects of the invention, which are described below.

[0007] In the following specification, the term "emitter" refers to a region of space that emits a greater flux of radiation than it absorbs, for at least one design wavelength.

[0008] In the following specification, the terms and "radiation source" refer to a region in space that emits or directs a net flux of radiation for at least one design wavelength, i.e., a radiation source may be an emitter or an optical element such as a lens or mirror that collects and directs radiation from an emitter.

[0009] In the following specification, the term "radiation" from an "emitter" or "radiation source" refers to radiation at or within a design wavelength. The methods described herein are generally applicable to radiation at wavelengths ranging from 200 nm to 100,000 nm, although the range of design wavelengths is generally much narrower. For germicidal applications, the design wavelength may be, for example, between 220 nm and 280 nm. For lighting devices and lighting applications, the design wavelength may be in the range between 400 nm and 750 nm. For near-infrared spectroscopy, the design wavelength may be, for example, in the range of 800 nm to 2500 nm.

[0010] In the following specification, the term "specular reflection" refers to reflection where the difference between the angle of incidence and the angle of reflection is less than 2 degrees. That is, the definition of specular reflection is expanded from the ideal case where the angle of reflection is equal to the angle of incidence to include a narrow distribution around the specular angle. Radiation reflected (or scattered) at angles outside the specular range is defined as diffuse.

[0011] In the following specification, the term "reflective" means specular, unless expressly defined as diffuse.

[0012] In the following specification, the term "mirror" means a smooth surface that is specularly reflective.

[0013] According to one aspect of the invention, which can be used independently or in combination with any of the other features described herein, there is provided a method for collecting radiation emitted from a three-dimensional emitter, comprising the steps of: collecting radiation emitted by the emitter with a plurality of optical directing components; A method is provided in which each optical directing component is for less than or equal to one-half of the solid angle through which radiation is emitted by the three-dimensional emitter.

[0014] According to one optional feature, which can be used together with the above definition or other features defined herein, the emitter has an axis of symmetry and the optical directing component is configured symmetrically with respect to the axis.

[0015] According to one optional feature, which can be used in conjunction with the above definition or other features defined herein, the collected radiation is directed to at least one aperture, the area of ​​the aperture being smaller than a surface area of ​​the three-dimensional emitter.

[0016] According to one optional feature, which can be used together with the above definition or other features defined herein, the aperture consists of a plurality of apertures, the combined area of ​​the apertures being smaller than a surface area of ​​the radiation source.

[0017] According to one optional feature, which can be used in conjunction with the above definition or any other feature defined herein, each optical directing component subtends no more than one third of a solid angle through which radiation is emitted by said three-dimensional emitter.

[0018] According to one optional feature, which can be used with the above definition or other features defined herein, each optical directing component subtends no more than ⅙ of a solid angle through which radiation is emitted by said three-dimensional emitter.

[0019] According to one optional feature that can be used with the above definition or other features defined herein, there are six equal-angle optical directing components around the emitter.

[0020] According to one optional feature, which may be used in conjunction with the above definition or any other feature defined herein, the optically directing component comprises a waveguide.

[0021] According to one optional feature, which may be used in conjunction with the above definition or any other feature defined herein, radiation from each waveguide is directed towards a radiation transmitting element.

[0022] According to one optional feature, which may be used in conjunction with the above definition or any other feature defined herein, the optical directing component comprises a lens.

[0023] According to one optional feature, which can be used in conjunction with the above definition or other features defined herein, the collected radiation is greater than 60% of the radiation emitted by the emitter for at least one design wavelength.

[0024] According to one optional feature that can be used with the above definition or any other feature defined herein, the emitter is a source of radiation.

[0025] According to one optional feature, which can be used together with the above definition or any other feature defined herein, the emitter is an emission tube of radiation.

[0026] According to one optional feature, which may be used in conjunction with the above definition or any other feature defined herein, the radiation source is in contact with at least one directing component.

[0027] According to one optional feature, which may be used together with the above definition or any other feature defined herein, at least one optical element of the optical directing component is integral with the radiation source.

[0028] According to one optional feature, which can be used in conjunction with the above definition or other features defined herein, all radiation from the radiation sources is collected and directed along a common path.

[0029] According to one optional feature that can be used with the above definition or other features defined herein, the emitter is an object to be observed and the radiation is illumination radiation from a separate source reflected from the emitter. The object to be observed is moving along a path, and the optical directing component preferably surrounds the path. In one configuration, the illumination radiation is transmitted along the path. Alternatively, the illumination radiation of the object is applied at angularly spaced positions around the path. In this configuration, the illumination radiation at the angularly spaced positions around the path is preferably applied in a slightly diverging path terminated by a radiation absorbing beam stop. In this configuration, the angularly spaced positions of the illumination radiation around the path are preferably interleaved with the optical directing component. In this configuration, the collected radiation is preferably directed to a device for analyzing the collected radiation, for example a spectrometer.

[0030] According to one optional feature, which may be used in conjunction with the above definition or any other feature defined herein, the at least one directing component consists of a plurality of optical elements, which are preferably refractive or reflective.

[0031] According to one optional feature, which may be used in conjunction with the above definition or any other feature defined herein, the plurality of optically directing components includes at least one common optical element.

[0032] According to one optional feature that can be used in conjunction with the above definition or other features defined herein, the optical directing components are configured to subtend substantially all of the solid angle into which the radiation is emitted, with each optical directing means subtending less than half of the emission solid angle.

[0033] In one configuration, the radiation source is an ionized gas.

[0034] According to one optional feature, which may be used in conjunction with the above definition or any other feature defined herein, the optical directing component is configured symmetrically with respect to the axis of the radiation source.

[0035] According to one optional feature, which may be used together with the above definition or other features defined herein, the path of the directional radiation does not intersect with the radiation source.

[0036] According to one aspect of the invention, which can be used independently or in combination with any of the other features described herein, there is provided a method for observing a three-dimensional emitter, comprising the steps of: moving the radiator along a path; applying illumination radiation to an emitter moving along a path; collecting radiation reflected by the emitter with a plurality of optical directing components; configuring optical directing components at angularly spaced locations about the path; A method is provided in which each optical directing component is for less than half the solid angle through which radiation is reflected by the three-dimensional emitter.

[0037] According to one optional feature, which can be used in conjunction with the above definition or other features defined herein, the collected radiation is directed to at least one aperture, the area of ​​the aperture being smaller than a surface area of ​​the three-dimensional emitter.

[0038] According to one optional feature, which can be used together with the above definition or other features defined herein, the aperture consists of a plurality of apertures, the combined area of ​​the apertures being smaller than a surface area of ​​the radiation source.

[0039] According to one optional feature, which can be used in conjunction with the above definition or any other feature defined herein, each optical directing component subtends no more than one third of the solid angle through which radiation is reflected by the three-dimensional emitter.

[0040] According to one optional feature that can be used with the above definition or other features defined herein, each optical directing component subtends no more than ⅙ of the solid angle of radiation emitted by the three-dimensional emitter.

[0041] According to one optional feature that can be used with the above definition or other features defined herein, there are six equal-angle optical directing components around the path.

[0042] According to one optional feature, which may be used in conjunction with the above definition or any other feature defined herein, the optically directing component comprises a waveguide.

[0043] According to one optional feature, which may be used in conjunction with the above definition or any other feature defined herein, the optical directing component comprises a lens.

[0044] According to one optional feature, which can be used with the above definition or other features defined herein, the collected radiation is, for at least one design wavelength, 60% or greater than the radiation reflected by the emitter, although this value may be higher.

[0045] According to one optional feature that can be used in conjunction with the above definition or other features defined herein, the optical directing components are configured to subtend substantially all of the solid angle through which radiation is reflected, with each optical directing means subtending no more than half of the reflected solid angle.

[0046] According to one aspect of the invention, which can be used independently or in combination with any of the other features described herein, there is provided a method for collecting radiation emitted from a three-dimensional radiation source, comprising the steps of: collecting radiation emitted by a radiation source with a plurality of optical directing components arranged at angularly spaced positions around the source; and transmitting the collected radiation to one or more end-use points; each optical directing component for less than half of a solid angle through which radiation is emitted by said three-dimensional radiation source; A method is provided wherein the collected radiation is greater than 60% of the radiation emitted by the radiation source for at least one design wavelength.

[0047] According to one optional feature, which can be used together with the above definition or other features defined in this specification, the radiation source has an axis of symmetry and the optical directing component is configured symmetrically with respect to the axis.

[0048] According to one optional feature, which can be used in conjunction with the above definition or any other feature defined herein, the collected radiation is directed to at least one aperture, the area of ​​the aperture being smaller than a surface area of ​​the three-dimensional radiation source.

[0049] According to one optional feature, which may be used together with the above definition or any other feature defined herein, at least one optical element of the optical directing component is integral with the radiation source.

[0050] According to one optional feature, which can be used in conjunction with the above definition or other features defined herein, all radiation from the radiation sources is collected and directed along a common path.

[0051] According to one aspect of the invention, which can be used independently or in combination with any of the other features described herein, there is provided a method for subjecting a reactive material in a reaction chamber to electromagnetic radiation, the method comprising the steps of: introducing electromagnetic radiation into a chamber; and increasing the probability of the electromagnetic radiation interacting with the reactive material by using multiple reflections to increase the optical path length of the electromagnetic radiation within the reaction chamber; the reaction chamber includes a plurality of pairs of opposing reflective surfaces of the chamber; at least 50% of the reflection from the reflective surface is specular, more preferably at least 80% or 90%; at least one of each pair of reflective surfaces is a concave mirror; each pair of reflective surfaces is configured to cause back and forth reflection of electromagnetic radiation between the reflective surfaces within a volume defined by the reflective surfaces; each pair of reflective surfaces are spaced apart from one another to define a first side of the volume on one side of the reflective surfaces and a second side of the volume on an opposing side of the reflective surfaces; A method is provided in which the pairs are configured side-by-side such that radiation escaping through a side of one volume enters a side of the next adjacent volume.

[0052] According to one optional feature that can be used with the above definition or other features defined in this specification, the multiple pairs define a stack of volumes side by side, and radiation can pass between each volume and the next adjacent volume.

[0053] According to one optional feature, which may be used together with the above definition or other features defined herein, the end volume of the volumes has a reflective sidewall on an outer one of its sides.

[0054] According to one optional feature, which may be used in conjunction with the above definition or any other feature defined herein, the reflective surface forms a side wall of the duct.

[0055] In one configuration, the flow is perpendicular to the sides.

[0056] In one configuration, the radiation is directed into a duct through which the fluid passes.

[0057] In one configuration, the radiation is directed generally longitudinally of the duct.

[0058] In one configuration, the radiation is directed at an angle to the length of the duct, and the radiation passes through a window in the sidewall of the duct.

[0059] According to one optional feature that can be used with the above definition or other features defined herein, a majority of the radiation path includes at least 10, and preferably more than 100, reflections from surfaces bounding the reaction chamber. In other words, the reaction chamber surfaces are configured such that a majority of the radiation path is confined to a volume within the reaction chamber and is incident on a reflective reaction chamber surface at least 10, and preferably more than 100, times before the radiation path exits the reaction chamber.

[0060] According to one optional feature, which can be used in conjunction with the above definition or any other feature defined herein, the reflective surfaces define at least one central optical axis extending therebetween and along which the reflection passes, and the source of radiation is positioned between the reflective surfaces at a position offset from the central axis such that a locus of the reflection moves towards the central axis.

[0061] According to one optional feature, which can be used together with the above definition or other features defined in this specification, the radiation source is positioned on one side of the at least one reflective surface of the reflective pair.

[0062] According to one optional feature, which can be used together with the above definition or any other feature defined herein, the reflective surface is a concave mirror and a source of radiation is positioned at a location on the at least one concave mirror, said source of radiation having a dimension less than 0.03 times the focal length of the mirror.

[0063] According to one optional feature, which may be used together with the above definition or any other feature defined herein, the source of the radiation source is positioned at the focal point of the concave mirror.

[0064] According to one optional feature, which can be used together with the above definition or other features defined herein, the offset between each beam after reflection and the next beam is less than the width of the beam, such that the beams form a complete curtain.

[0065] According to one optional feature that can be used with the above definition or any other feature defined herein, an inlet port for receiving reactants and an outlet port for discharging products are provided, with an absorbing surface shaped and configured to stop the transmission of electromagnetic radiation from the interior of the chamber to an exterior point, in this configuration, the inlet and outlet ports are preferably not on the axis of symmetry of the reaction chamber.

[0066] According to one optional feature that can be used with the above definition or other features defined herein, at least a portion of the chamber wall diffusely reflects electromagnetic radiation. This feature enhances the uniformity of the radiation field in the reaction chamber. Empirically, dust, manufacturing defects, and small scratches are enough to provide sufficient diffuse scattering (a few percent) for uniformization purposes.

[0067] According to one optional feature, which can be used with the above definition or any other feature defined herein, the reactive material is entrained in a fluid flow, the fluid being a liquid or a gas.

[0068] According to one optional feature that can be used with the above definition or other features defined herein, the electromagnetic radiation is UVC radiation, the reactive material is a microorganism selected from the list of bacteria, viruses, protozoa, helminths, yeasts, molds, or fungi, and the UVC radiation inactivates the microorganism. Preferably, the UVC radiation comprises radiation having a wavelength between 220 nm and 280 nm.

[0069] According to one optional feature, which can be used in conjunction with the above definition or other features defined herein, the electromagnetic radiation is at least partially collimated to travel primarily back and forth between the reflective surfaces.

[0070] According to one aspect of the invention, which can be used independently or in combination with any of the other features described herein, there is provided a method for subjecting a reactive material in a reaction chamber to electromagnetic radiation, the method comprising the steps of: introducing a predetermined wavelength of electromagnetic radiation into the chamber; increasing the probability of the electromagnetic radiation interacting with the reactive material by using multiple reflections from reflective surfaces of the reaction chamber to increase the optical path length of the electromagnetic radiation through the reaction chamber for the amplitude of the electromagnetic radiation to exceed a threshold; at least one reflective surface of the reaction chamber comprises a metallic reflective wall at least partially coated with a layer of a material having a high refractive index and low absorption of radiation at a predetermined wavelength; Methods are provided in which the layer of material has a thickness selected to increase the reflectivity of radiation at the reflective surface to a value greater than that of the metal layer alone. NThe radiation field in the reaction chamber is calculated by dividing the reaction chamber into an array of small volume elements and summing the path amplitudes in each volume element. The threshold amplitude is selected such that amplitudes below the threshold do not change the calculated radiation field in the volume element by more than an acceptable amount of error. Empirically, a threshold amplitude of 0.0001 has been found to work well, for an initial amplitude of 1.0000. Other thresholds may be used. In this configuration, the material is preferably ZrO2. In this configuration, the thickness of the high refractive index material is preferably varied at different points on the surface. In this configuration, the thickness of the high refractive index material is preferably varied at different points on the surface depending on the angle of incidence of the radiation on the surface, such that the thickness of the high refractive index material increases at points of greater incidence. In this configuration, the high refractive index material is preferably omitted, such that the metal walls are bare at points of incidence greater than a predetermined value. The walls are preferably aluminum, although other reflective materials may be used.

[0071] In this configuration, the material preferably provides increased hardness relative to the metal wall.

[0072] According to one aspect of the invention, which can be used independently or in combination with any of the other features described herein, there is provided a method for collecting radiation emitted from a radially symmetric source, comprising the steps of: providing a first parabolic reflector and a second parabolic reflector, each having a reflective surface defining a rear neck and a forwardly projecting mouth; positioning a first parabolic reflector and a second parabolic reflector back-to-back such that the first parabolic reflector and the second parabolic reflector intersect at a neck and each reflective surface extends from the respective neck to the respective mouth; positioning a radiation source at a focus of each parabolic reflector; and collecting radiation emitted from the mouth of each parabolic reflector; A method is provided whereby radiation emitted by the source in a direction away from the mouth of each reflector enters the other reflector in a manner that avoids it being reflected back to the source where it would be absorbed. In this configuration, radiation from each reflector is preferably collected separately. Alternatively, radiation from both reflectors is combined and transmitted to a common end use point.

[0073] In this configuration, the source and the parabolic reflector are preferably symmetric about the longitudinal axis.

[0074] In this arrangement, there is preferably provided an optical guide member located within each parabolic reflector at a location on its axis spaced from the source such that radiation emitted in a direction beyond the mouth and thus missing the reflecting surface is redirected. In this arrangement, the optical guide member is preferably a lens that collimates the radiation along the axis of the parabolic reflector. Alternatively, the optical guide member is a mirror that redirects the radiation onto one or the other of the parabolic reflectors.

[0075] According to one optional feature that can be used with the above definition or any other feature defined herein, the source is an emitting cylindrical tube of radiation.

[0076] The above defined aspects of the invention may provide a solution to the three limitations described above for extended sources. For illustrative purposes, the method of the invention is described for a cylindrical source, which may be, for example, a gas discharge lamp or a linear filament emitting radiation. The method described herein may be applied to more complex geometries without loss of generality by enclosing the more complex geometries within a simple imaginary surface, such as a cylinder or a sphere, or by applying the method described herein to each volume element of the complex shape, each volume element being approximated as a simple primitive, such as a cylinder or a sphere. The light source may be, for example, a grain kernel enclosed in a cylinder.

[0077] According to an important feature of the invention, an aperture and a source of electromagnetic radiation are provided, the surface area of ​​the source of electromagnetic radiation being equal to or greater than the surface area of ​​the aperture, and at least a portion of the radiation provided by the radiation source is directed away from the aperture. Specifically, the dot product between a vector directed from at least one radiation origin on or in the radiation source to the center of the aperture and the vector direction of at least some of the radiation from that point is less than zero. For example, atoms in a gas discharge tube can emit radiation in all directions with equal probability. In this case, half of the directions have a component opposite to the direction from the atom to the aperture, resulting in a dot product less than zero. For example, the surface normal to a point on the surface of a grain of cereal can be directed opposite to the direction from the surface point to the aperture. In this case, the dot product between the aperture direction and the radiation direction is less than zero for all radiation scattered or reflected from said surface point.

[0078] In one embodiment of the invention as defined above, the solid angle relative to the emission area of ​​the source is divided into a plurality of regions and optical directing means are applied to each region separately. The optical directing means may be diffractive, reflective, refractive, or any combination thereof. The optical directing means may include a diffractive surface such as a Fresnel lens, a mirror, a lens, a waveguide, or any combination thereof. Each optical directing means receives a radiative flux at an input face with a first area and directs said radiative flux to an output face with a second area.

[0079] According to an important feature of the invention as defined above, a plurality of collector assemblies are provided, each collector assembly receiving radiation from the radiation source through its input face over a different range of solid angles, and at least one collector assembly receives at least some radiation from a direction away from the aperture, i.e. at least one collector assembly receives radiation for which the dot product of the radiation direction and the aperture direction is less than one.

[0080] The term optical assembly herein refers to a set of one or more logical optical elements that cooperate to transmit radiant energy from a first spatial distribution of radiant energy at an input face (proximate the radiation source) to a second spatial distribution of radiant energy at an output face (proximate the aperture). The input and output faces are curved and may or may not correspond to a material interface. Each logical optical element corresponds to a physical optical element. Each physical optical element may be included in multiple sets of logical optical elements. That is, a single physical optical element may perform the same function for multiple sets of logical optical elements. The optical elements may be diffractive, reflective, refractive, or any combination thereof.

[0081] A simple example is a cylindrical emitter with a circular cross section with two optical collecting assemblies 180 degrees apart. The first collecting assembly receives the emitted flux at angles between 0 and 180 degrees and produces a first (imperfect) collimated beam directed at 90 degrees. The second collecting assembly receives the emitted flux at angles between 180 and 360 degrees and produces a first (imperfect) collimated beam directed at 270 degrees. The first and second beams can be made collinear by including a prism, corner cube, or similar optical element in one of the optical collecting assemblies to rotate the direction of the corresponding beam by 180 degrees. In this example, all of the flux is at least imperfectly collimated and none is reflected back towards the source and absorbed. However, aberrations increase with the angular range allowed by the optical elements in the directing means. Aberrations can be at least partially compensated for by using multiple lenses in each optical collecting assembly, but this approach increases both cost and light loss. Therefore, it is preferable to divide the emission angular range into smaller angular ranges, for example six angular ranges of 60 degrees each.

[0082] According to an important feature of the invention defined above, the multiple light collector assemblies direct radiation from the radiation sources to a common photoreaction chamber. In some embodiments, each light collector assembly directs radiation from a radiation source to a separate port on the common photoreaction chamber. In some embodiments, the multiple light collector assemblies direct radiation from the radiation sources to a common port on the common photoreaction chamber.

[0083] In accordance with an important optional feature of the invention defined above, each logical concentrator assembly includes a logical collimation subassembly operative to reduce the angular divergence of radiation at an output face of the logical concentrator assembly.

[0084] According to an important optional feature of the invention defined above, the plurality of logical collector assemblies includes a logical collimation subassembly that corresponds to the same physical collimation optical assembly, i.e. the physical collimation assembly combines radiation from the plurality of logical collector assemblies and outputs a radiation beam with a smaller angular divergence than the input from the collector assembly.

[0085] According to one aspect of the invention, which can be used independently or in combination with any of the other features described herein, there is provided a method for decontaminating an object after potential contamination with one or more pathogens, comprising: generating a beam of radiation configured to inactivate pathogens; directing a beam at an object; and controlling the beam to deliver different doses of radiation in the beam to different locations on the object depending on properties of the object at the different locations.

[0086] According to one optional feature, which can be used with the above definition or any other feature defined herein, the different doses of radiation applied by the beam to different locations are calculated based on the concentration of the pathogen present at each location and the probability of the pathogen being transmitted from each location to a host species, the dose at each location being selected to minimize the probability of transmission from the location to the host species, which may be, for example, a human.

[0087] According to one optional feature that can be used with the above definition or other features defined herein, the different doses of radiation applied by the beam to different locations are calculated based on the total dose available to all locations, the concentration of pathogens present at each location, and the probability of transmission of the pathogens to the host species from each location, and the dose at each location is selected to minimize the probability of transmission from the location to the host species subject to a total dose constraint.

[0088] According to one optional feature that can be used with the above definition or other features defined herein, the different doses of radiation applied by the beam to different locations are calculated based on the concentration of pathogens present at each location and the probability of the pathogens being transmitted from each location to the host species, and the dose at each location is selected to reduce the pathogen concentration at each location below a predetermined threshold concentration.

[0089] According to one optional feature, which can be used with the above definition or other features defined herein, an initial pathogen concentration at each location is estimated by a statistical model based on previously measured pathogen concentrations for that location, and a dose is calculated to reduce the initial pathogen concentration below a predetermined threshold.

[0090] According to one optional feature that can be used with the above definition or other features defined herein, the predetermined threshold pathogen concentration for each location is based at least in part on a probability of transmission from the location to the host species. The probability of transmission for each location can be based on empirical measurements for that location or statistical inference from known transmission cases.

[0091] According to one optional feature, which can be used in conjunction with the above definition or other features defined herein, the beam is controlled based on reflectivity, scattering, and absorptivity as a function of the angle of incidence at the point.

[0092] According to one optional feature, which may be used in conjunction with the above definition or other features defined herein, the beam is controlled based on information about the dose sensitivity at the location.

[0093] According to one optional feature, which may be used in conjunction with the above definition or other features defined herein, the beam is controlled based on the probability of contamination at and adjacent locations.

[0094] According to one optional feature, which may be used in conjunction with the above definition or other features defined herein, a sensor is provided for measuring at least one of temperature, pressure, humidity, and molecular composition of the fluid between the surface location and the source.

[0095] According to one optional feature, which can be used in conjunction with the above definition or other features defined herein, the beam is controlled based on a probability that contamination at the location has been transferred to the second surface of the location by the contact.

[0096] According to one optional feature, which can be used in conjunction with the above definition or other features defined herein, the beam is controlled based on the probability that contamination at the location can be transmitted to the second surface.

[0097] According to one optional feature, which may be used with the above definition or other features defined herein, the beam is controlled based on pathogen reduction goal input from a user.

[0098] According to one optional feature that can be used in conjunction with the above definition or other features defined herein, the beam is controlled based on a human operator moving and directing the beam in response to commands and feedback from a control system.

[0099] According to one optional feature that can be used with the above definition or other features defined in this specification, the beam is controlled based on the position of a robotic platform that guides the decontamination system along a controlled path relative to the object to be decontaminated.

[0100] According to one optional feature that can be used with the above definition or other features defined herein, the beam is controlled based on a subsystem that measures the position and orientation of the beam relative to the object to be decontaminated.

[0101] According to one optional feature that can be used with the above definition or other features defined herein, the beam is controlled based on a measured source intensity, i.e., the source intensity is measured and the time that the beam is directed to each point on the object to be decontaminated to provide a threshold dose of radiation is calculated based on the radiation source intensity.

[0102] According to one optional feature that can be used with the above definition or other features defined herein, the beam is controlled based on measurements of radiation reflected or scattered from the surface location. That is, the reflected or scattered radiation is a known percentage of the incident radiation, and the time that the beam is directed to each location on the object to be decontaminated is calculated to deliver at least a threshold dose based on the known percentage of the measured scattered or reflected radiation and the collected scattered or reflected radiation. In some embodiments, the measured radiation may have a different wavelength than the radiation used for decontamination. For example, the measured radiation may be blue with a wavelength of 470 nm, and the decontamination radiation may be UVC with a wavelength of 270 nm.

[0103] According to one optional feature that can be used in conjunction with the above definition or other features defined herein, the method includes collecting a multispectral image of at least a portion of an object; determining, at least in part, a type of contamination present at different locations on the object by analyzing the multispectral image to determine an area of ​​the multispectral image corresponding to each location on the object; comparing a spectrum from the area of ​​the multispectral image corresponding to each location on the object to a reference spectrum to determine a type of contamination present at each location on the object; and directing a beam to each location on the object based at least in part on the type of contamination present at the location.

[0104] According to one optional feature, which can be used with the above definition or any other feature defined herein, the method includes collecting a sample from the surface location before or after irradiation, and the collected sample is analyzed for viable pathogens.

[0105] According to one aspect of the invention, which can be used independently or in combination with any of the other features described herein, a method is provided for collecting samples from a surface location before or after irradiation by an agitator and collector.

[0106] According to one optional feature that can be used with the above definition or other features defined herein, the agitator and collector are used to randomly sample locations on the surface of the object, and the collected material is analyzed to provide detailed information about materials and contaminants present at the locations.

[0107] According to one optional feature, which can be used with the above definition or other features defined herein, information from the randomly selected locations is used to build a statistical model for detecting systematic problems with the sanitation procedure.

[0108] According to one optional feature, which can be used with the above definition or other features defined herein, information from the randomly sampled locations is used to build a statistical model that predicts the probability of contamination as a function of location.

[0109] According to one optional feature that can be used with the above definition or other features defined herein, location dependent probabilities are used to optimize UVC dose allocation.

[0110] According to one optional feature, which may be used with the above definition or any other feature defined herein, a position verification system is provided as a component of the source, the position verification system operative to determine the position and orientation of the source relative to the object to be decontaminated.

[0111] According to one optional feature that can be used in conjunction with the above definition or other features defined in this specification, the location verification system includes a camera operating in conjunction with software for tracking the location and orientation of the source as a function of time.

[0112] According to one optional feature that can be used in conjunction with the above definition or other features defined in this specification, the multiple sample locations include a pattern of markings used by the position verification system to calculate the location and orientation of the source.

[0113] According to one optional feature, which can be used with the above definition or other features defined herein, the position verification system includes a device for measuring a distance from a source to a surface point.

[0114] According to one optional feature that can be used with the above definition or other features defined herein, information is displayed on an overlay image to an operator, the overlay image including an image of the surface to be decontaminated together with a suitable representation of the dose received at each location versus the dose required at each location.

[0115] According to one aspect of the invention, which can be used independently or in combination with any of the other features described herein, there is provided a method for applying electromagnetic radiation to a liquid flow in a chamber, the method comprising the steps of: introducing electromagnetic radiation into a chamber; and increasing the probability of the electromagnetic radiation interacting with the reactive material by increasing the optical path length of the electromagnetic radiation within the reaction chamber using multiple reflections; the reaction chamber includes at least one pair of opposing reflective surfaces of the chamber; at least 50% of the reflection from the reflective surface is specular, more preferably at least 80% or 90%; at least one of each pair of reflective surfaces is a concave mirror; each pair of reflective surfaces is configured to cause reflection of electromagnetic radiation passing between the reflective surfaces within a volume defined by the reflective surfaces; A method is provided in which the chamber is a fitting adaptor for attachment to a source of liquid.

[0116] According to one optional feature, which may be used in conjunction with the above definition or any other feature defined herein, the adapter comprises a dispensing nozzle.

[0117] According to one optional feature that can be used with the above definition or other features defined herein, the adapter includes one or more couplings configured for attachment to different sources. For example, the adapter may include a threaded portion, a press fit, or a clip.

[0118] According to one optional feature, which may be used in conjunction with the above definition or any other feature defined herein, the adapter includes a filter.

[0119] According to one aspect of the invention, which can be used independently or in combination with any of the other features described herein, there is provided a method for applying electromagnetic radiation to a liquid flow in a chamber, the method comprising the steps of: introducing electromagnetic radiation into a chamber; and increasing the probability of the electromagnetic radiation interacting with the reactive material by increasing the optical path length of the electromagnetic radiation through the reaction chamber using multiple reflections; A method is provided in which the chamber is configured in association with a filter for attachment to a source of liquid. [Brief description of the drawings]

[0120] [Figure 1] 1 is a schematic cross-sectional view of a prior art parabolic reflector; [Diagram 2] 1 is a schematic cross-sectional view of radiation directed in a single direction from a cylindrical source by a lens; [Diagram 3] 1 is a schematic cross-sectional view of radiation being directed in a single direction from a cylindrical source by an array of lenses and mirrors. [Figure 4A] FIG. 2 is a schematic side view of an arrangement for collecting radiation scattered by an object within a tube. [Figure 4B]FIG. 13 is a schematic side view of an arrangement for unidirectional collection by a waveguide of radiation radially reflected and scattered by an object in a tube. [Diagram 5] FIG. 1 is a schematic diagram of an arrangement for directing radiation onto an object within a tube and collecting reflected and scattered radiation for measurement. [Figure 6A] A schematic cross-sectional view of a configuration for directing radiation in a single direction from a cylindrical source by means of a compound parabolic reflector and a lens. [Figure 6B] FIG. 6B is a schematic cross-sectional view of a configuration for directing radiation in two directions from a cylindrical source by the compound parabolic reflector and lens of FIG. 6A. [Figure 7] FIG. 6B is a schematic cross-sectional view of a configuration for directing radiation from a cylindrical radiation source through two ports into a photochemical reaction chamber using the compound parabolic reflector of FIG. 6A. [Figure 8] FIG. 8 is a schematic cross-sectional view of an arrangement for directing radiation into a chamber for fluid flow that can use the discharge arrangement of FIG. 7 or can use a cylindrical source at the focus of one of the concave reflectors. [Figure 8A] 9 is an alternative schematic cross-sectional view of an alternative arrangement for directing radiation into a chamber for fluid flow, of a similar arrangement to FIG. 8. [Figure 9] 8A , showing a further embodiment according to the present invention, in which the wall is coated with a reflective layer of ZrO 2 . FIG. [Figure 10] 10 is a graph showing the effect on reflectance of the configuration of FIG. 9 in which the walls are coated with a reflective layer of ZrO2. [Figure 11] FIG. 4 illustrates an arrangement using the directional decontamination beam of FIG. 3 for decontaminating an object such as a vehicle seat between uses by different passengers. [Figure 12] 12 is a flowchart showing the operation of the control system having the configuration of FIG. 11. [Figure 13] 12 is a flowchart showing the operation of the control system having the configuration of FIG. 11. [Figure 14]FIG. 1 shows a schematic diagram of an arrangement for disinfecting a water stream. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0121] Fig. 1 shows a schematic of the characteristics of a prior art parabolic reflector. A radially symmetric radiation source 1 with radius r is positioned at the focal point F of a parabolic reflector 2. The distance from the vertex V to the focal point F is f and the height of the parabolic reflector from the vertex V to the edge D, expressed in units of f, is nf, where n is a real number greater than 1. Radially emitted rays from the radiation source 1 are reflected by the parabolic reflector 2 parallel to the parabolic axis N. Radially emitted rays within an angle 2α, subtended by the point AFB, are reflected by the parabolic reflector 2 back to the radiation source 1 and undergo absorption. For a radially symmetric source, the ratio of lost energy to absorption is kα / π, where k is the geometrically averaged absorption constant, α=tan -1 (r / f) It is.

[0122] The rays emitted radially by the radiation source 1 within the angle 2β defined by the point CFD are not incident on the parabolic reflector 2 and are therefore not collimated in the direction of the parabolic axis N. The angle β is β=tan -1 [2n 1 / 2 / (n-1)] is given by:

[0123] A ray of light emitted by the radiation source 1 and incident on the parabolic reflector at an angle γ=π-α-β defined by the point AFC is reflected substantially parallel to the parabolic axis N.

[0124] For a general point G inside the radiation source 1, rays emitted radially along the line FE are reflected parallel to the paraboloid axis N as shown in 3, while rays emitted towards a general point H on the paraboloid reflector are reflected in the general direction of N. As the ratio r / f increases, the angular divergence δ from the direction of N generally increases. Thus, when r / f is small, the rays are well collimated, and when r / f is large, the collimation is poor. The rays approximately parallel to the paraboloid axis N can be focused to form an image on the aperture plane by a perfectly collimated ray imaged to a point at the center of the aperture and rays with increasing angular divergence δ imaged increasingly far from the center of the aperture. The fraction that is not focused on the aperture is a function h(r / f). That is, the required aperture size increases with the angular divergence and the r / f ratio. Furthermore, most of the rays emitted into the angle 2β have a large divergence from the paraboloid axis N. Although the rays at angle 2β can be imaged onto the aperture, the focal length of the focusing element is different from the focal length required to image the rays at angle γ onto the aperture. Thus, the total optical loss in the prior art system is approximately Loss = (α + β + h(r / f)γ) / π It is.

[0125] The inventive configurations discussed below eliminate the α and β terms and reduce the magnitude of the γ term.

[0126] 2 shows, in a schematic manner, six optical embodiments of the present invention generally designated 10. That is, in a single drawing, six different options are shown at six locations around the axis of the source. In reality, an actual embodiment would use the same options at each location, but for ease of illustration, this has not been included as a separate diagram for each option.

[0127] A cylindrical tube emitter 11 has an axis 12 perpendicular to the plane of the drawing and is bounded by a transparent container 13. The container 13 may include a reflective section 14 positioned at the intersection of optical regions 15 that reflects radiation back into the tube emitter 11 as shown at 16. The tube emitter 11 is surrounded by six optical lenses 21, 22, 23, 24, 25 and 26. The lenses are preferably anti-reflective coated to reduce Fresnel reflection losses. For convenience of illustration, each lens subtends an equal angle, although there is no requirement that the subtended angles be equal. In some embodiments, the subtended angles of each may be different.

[0128] Lens 21 may be a cylindrical lens that receives radiation from source 11 and forms a collimated beam 27 that passes directly through an aperture 28 in chamber wall 29. Cylindrical lenses are simple to fabricate and collimate radiation incident near the optical axis well, but suffer from aberrations at the edges. As shown, radiant power incident near the optical axis is collimated and the beam 27 passes directly through aperture 28 to chamber 30. The width of beam 27, shown at 27A, is smaller than the diameter of tube emitter 11. In some embodiments, a reflective coating may be placed on or adjacent tube emitter 11 over a small area near the junction between two lens sectors 15, as shown at 14. Reflective region 14 has just enough angular range to block radiation that is not properly focused on the aperture at the periphery of the optical element due to aberrations. A fraction of the power reflected by reflective region 14 is re-emitted in random directions, with a high probability of being re-emitted in a direction that is properly focused on the aperture. In embodiments that use lenses designed to correct aberrations, the reflective region may be omitted.

[0129] Lens 22 collects radiant power from cylindrical tube emitter 11 and directs a collimated beam 31 incident on folding mirror 32. Folding mirror 32 redirects the collimated beam along a desired optical axis perpendicular to chamber wall 29 onto focusing lens 33. Focusing lens 33 focuses the collimated beam through aperture 34, where radiation passing through aperture 34 is recollimated by lens 35 and enters chamber 30 as collimated beam 36. The beam diameter of recollimated beam 36 is a fraction of the beam diameter of beam 31 and is smaller than the diameter of emitter tube 11. That is, the emission from tube 101 in the direction of lens 22 is compressed into an area substantially smaller than the dimensions of emitter tube 11. Note that the beam divergence of beam 36 increases in proportion to the ratio of beam diameter 31 to beam diameter 36. In embodiments in which aperture 34 and chamber 30 are elements of a reaction chamber for sterilization as described in the above-cited MPS patents by the present inventor, a beam divergence below the threshold is acceptable and even slightly advantageous, so long as the increased beam divergence reduces the probability that radiation will be reflected back through aperture 34 within the chamber. The threshold beam divergence is selected so that the majority of the radiative power of the beam passing through aperture 34 is directly incident on a highly reflective concave end mirror (not shown) of reaction chamber 30. The radiative power incident on the concave end mirror is constrained by the chamber geometry to propagate primarily along the chamber optical axis.

[0130] Lenses 23 and 23B show diagrammatically that a multi-lens system may be used to correct aberrations and collimate the incoming radiation power over an increased angular range. As shown at 23C and 23D, the surfaces of lens 23 are non-cylindrical. Lens surfaces 23C and 23D are shaped to cooperate with additional lens 23B to increase the numerical aperture and reduce the angular divergence of the collimated radiation. Collimated beam 37 may be directed through an aperture using, for example, a folding mirror (not shown), as shown for the optical path beginning with lens 22 described above.

[0131] Lens 24 and concave mirrors 38 and 39 show diagrammatically an alternative configuration to that shown for lens 22 for projecting radiation through a small aperture. Lens 24 is shaped to admit and collimate radiation power over a wider angular range than a cylindrical lens. Concave mirror 38 focuses the radiation collected and collimated by lens 24, which is recollimated by concave mirror 39 to form a collimated beam 40 that passes through aperture 41 into chamber 30. In the configuration shown, concave mirrors 38 and 39 operate to rotate the direction of the radiation beam by 180 degrees and expand the beam diameter by less than one factor at the ratio of their focal lengths. Mirrors 38 and 39 are preferably high reflectivity dielectric mirrors with reflectivities optimized for the mean angle of incidence (45 degrees as shown), as described in the MPS application cited above. Different angles of incidence may be used with dielectric mirrors optimized for different angles of incidence.

[0132] Lens 25 is displaced from emitter tube 11, subtending a full 60 degree angle of the sector as shown at 42. By increasing the distance between the emitter tube and the lens, a longer focal length lens can be used with less edge aberration. Lens 25 produces a collimated beam 43 having a width greater than the diameter of emitter tube 11. Beam 43 can be reduced in diameter and then directed through an aperture as shown for the optical path starting from lenses 22 and 24. Specifically, plane mirror 32 is oriented to geometrically reduce the width of (imperfect) collimated beam 31. Concave mirrors 38 and 39 function to expand the (imperfect) collimated beam from lens 24 by a magnification factor less than one.

[0133] Lens 26 collects the radiant power from emitter tube 11 and directs collimated radiation onto optical fiber array 44. Individual optical fibers may transmit radiation to any location on chamber wall 29. In a first optical fiber embodiment, collimated radiation enters fiber 45 at 46 and is transmitted to chamber 30 where it is emitted at 47 with an angular divergence corresponding to the fiber numerical aperture. In this case, the angular divergence of the radiation delivered to chamber 30 can be controlled by selecting an appropriate numerical aperture fiber. In a second optical fiber embodiment, collimated radiation enters fiber 48 and is emitted at 49 with an angular divergence determined by the numerical aperture of fiber 48. The radiation emitted at 49 is recollimated by ball lens 50 and a collimated beam 51 enters chamber 30. In this case, a larger numerical aperture fiber can be selected since collimation at the chamber is determined by the ball lens.

[0134] Thus, the embodiment of Figure 2 provides a method for collecting radiation emitted from a three-dimensional object defined by a source 11, where the radiation emitted by the object is collected by a plurality of optical directing components 21-26, each optical directing component subtending less than half the solid angle through which radiation is emitted by said three-dimensional object.

[0135] As shown, the object or source 11 has an axis of symmetry and the optical directing components 21-26 are arranged symmetrically about the axis.

[0136] As shown, the collected radiation is directed to at least one aperture 41, the area of ​​which is smaller than the surface area of ​​the three-dimensional object.

[0137] As shown, there can be multiple apertures, with the total area of ​​the apertures combined being less than the surface area of ​​the radiation source.

[0138] As shown, each optical directing component subtends less than one third of the solid angle through which radiation is emitted by the three-dimensional object.

[0139] As shown, each optical directing component subtends no more than 1 / 6 of the solid angle through which radiation is emitted by the three-dimensional object.

[0140] As shown, there are six equiangular optical pointing components around the object.

[0141] FIG. 3 shows a symmetrical configuration used to direct substantially all of the radiation emitted, scattered or reflected from the source 11 in one direction as shown at 70. An array 60 of lenses 61, 62, 63, 64, 65 and 66 are arranged radially about the axis 12 of the source 11 at equal angular intervals. For illustrative purposes, an array of six lenses is shown. The number of lenses may be as few as three or as many as 36 or more. The number of lenses in the array is preferably between six and twelve. The lenses may be separate pieces mounted against a support structure (not shown) or may be fabricated as a single piece. The lens array 60 is preferably mounted on a frame 67. The frame 67 centers the lens array 60 about the axis 11 and allows translation along the axis 12 for purposes of accessing and maintaining the source 11. Each lens is preferably positioned at a radial distance from the axis 11 that is between two and three times the radius of the source 11. As the radial distance increases, the angular divergence of the light rays relative to each lens axis decreases, leading to improved collimation of the output beam of each lens. As the radius of the lens array 60 increases, the volume of lens material required increases, leading to higher cost. Empirically, the best compromise between angular divergence and cost is a lens array radius of about 2.4 times the source radius.

[0142] Each lens produces a collimated beam. Lens 66 produces collimated beam 68, which has less angular divergence than the rays incident on lens 66. In the illustrated embodiment, the rays in beam 68 are approximately parallel. In an alternative embodiment (not shown), the rays in beam 68 may converge, and a second optical element, e.g., a mirror, is positioned along the beam axis with a curvature and position designed to produce a beam of smaller width. The reduction in beam width is proportional to the ratio of the focal lengths of the mirror and lens. Lens 61 receives radiation from source 11 and produces collimated beam 68A, which is incident on mirror 72, which produces reflected beam 69 in the direction of axis 70. Mirror 76 and lens 65 are symmetrical and equivalent to lens 61 and mirror 72. Similarly, lenses 62 and 64 form a symmetric pair on mirrors 73 and 75, which produces an increased beam width (as shown). This pair is preferably in the second embodiment, where the lens and mirror curvatures interact to produce a beam with a smaller beam width. As shown, the beam from lens 63 is anti-parallel to axis 70 and its direction is aligned with axis 70 using two folding mirrors 74 and 71. Thus, the radiation from source 11 is split into six portions, with each portion collimated and aligned with axis 70. In effect, the illustrated configuration aligns more than 50% or 80% or 90% of the radiation from source 11 with axis 70 at less than 5 degrees of divergence. By comparison, prior art parabolic reflectors collimate approximately 55% of the radiation to within 5 degrees of the axis.

[0143] In some embodiments, the directional beam produced by the configuration of FIG. 3 may be used to focus exposure to radiation produced by source 11 to a defined area. For example, the directional beam may be ultraviolet radiation used to decontaminate surfaces that are variable in height relative to the beam axis 70. In the configuration shown, the dose received is substantially height independent (neglecting atmospheric absorption and residual beam divergence). The configuration may be used, for example, to sanitize seats in transportation vehicles. For example, the configuration of FIG. 3 may be used to increase the radiation flux from an infrared source projected onto a sample material for subsequent spectroscopic analysis. The sample material may be, for example, a grain. The spectroscopic analysis is preferably performed by a spectrometer based on the above-cited HEMS patent by the present inventor. In this case, the increased photon efficiency is combined with the increased photon efficiency of the HEMS spectrometer to provide an improved signal-to-noise ratio.

[0144] In an alternative embodiment, the configuration shown in Figure 3 further includes a focusing element, such as a lens or mirror (not shown), that focuses the six beams through an aperture, which may be in a wall of the photochemical reaction chamber, for example, as discussed in the above-cited MPS patent by the present inventor.

[0145] FIG. 4A shows a side view of an arrangement for illuminating an object in a tube and collecting scattered and reflected radiation from the object. The tube may be, for example, a tube for transporting cereal grains. The grains 80 are enclosed in a transparent cylindrical tube 81 and travel in the direction of the tube axis, as shown at 82. The tube may be, for example, quartz, fused silica or sapphire. The grains may be illuminated by probe radiation along the tube axis, as shown at 83, and the reflected and scattered radiation 84 enters a waveguide 91. The probe radiation may be, for example, near infrared radiation with a wavelength between 0.8 microns and 3 microns that propagates through quartz, fused silica or sapphire. Alternatively, the probe radiation 85 may enter the tube 81 at an angle 86, pass through the tube wall and enter the grains 80. The scattered or reflected radiation 87 from the grains 80 enters the waveguide 94. The radiation entering the waveguides 91 and 94 is transmitted to a common output port for measurement.

[0146] FIG. 4B shows a configuration generally designated 400 with a radiation source 401 radially symmetric about an axis 402. The radiation source 401 is abutted by six waveguides 411, 412, 413, 414, 415 and 416. The six waveguides are spaced at equal angles and form a hexagonal ring that completely surrounds the source 401. The waveguides optionally include an anti-reflection coating 421 designed to reduce Fresnel reflections at the waveguide interfaces for a range of design wavelengths. For example, the radiation source 401 may be a mercury vapor gas discharge tube that emits radiation centered around a wavelength of approximately 256 nm. For example, the waveguides may be fabricated from fused silica (SiO2), which has a refractive index of approximately 1.498 at 256 nm. Radiation incident from the source at all angles of incidence refracts into the waveguide, and all refracted radiation is incident on the waveguide sidewall 422 above a critical angle, provided that the waveguide curvature is kept below a threshold. As shown in FIG. 4B, the waveguides 412, 413, 414, 415, and 416 follow curved paths to a common output plane 430. The illustrated waveguide curvatures are greater than the threshold for illustrative purposes only. In practical embodiments, the curvature is kept below the threshold so that total internal reflection occurs and the radiant energy is transferred from the radiation source to the plane 430 without loss. In embodiments where the cross-sectional area of ​​each waveguide is substantially constant (within manufacturing tolerances), the distribution of ray angles relative to the waveguide axis is the same at the input (source) end and the output (plane 430) end. As the number of waveguides increases, the distribution of ray angles incident on each waveguide shifts to lower angles. In other words, as the number of waveguides increases, the angular divergence from the average direction at each waveguide decreases (the angular range of the source for each waveguide decreases). Radiation emitted through the waveguide ends at plane 430 is focused by lens 431 through focal point 432 onto aperture 434. Lens 433, located at aperture 434, reduces the angular divergence of the radiation emitted into photoreaction chamber 440, as shown at 435.

[0147] While the configuration shown in FIG. 4B is shown for collating and directing light from a source, it can also be used with light emitted, reflected, or scattered by an object to be observed, as in FIG. 4A.

[0148] Thus, in Figures 2 and 3, a method is provided for collecting radiation emitted from a three-dimensional source 11, where the radiation emitted by the radiation source 11 is collected by a plurality of optical directing components 21-26 in Figure 2 and 61-66 in Figure 3 that are positioned at angularly spaced locations about the radiation source. The collected radiation is transmitted to one or more end points of use by one of a number of optional configurations.

[0149] Each optical directing component is oriented such that for less than half the solid angle through which radiation is emitted by the three-dimensional emitter, the collected radiation is greater than 60% of the radiation emitted by the body for one or more design wavelengths. In some configurations, this allows 50%, 80%, or 90% of the radiation from source 11 to be aligned with axis 70 with a divergence of less than 5 degrees for one or more design wavelengths.

[0150] Typically, the object has an axis of symmetry and the optically directing components 21-26 are arranged symmetrically with respect to the axis.

[0151] In some cases, the collected radiation is directed to a single aperture 41, the area of ​​which is smaller than the surface area of ​​the three-dimensional object.

[0152] In other cases, radiation is directed to multiple apertures, the combined area of ​​the apertures being less than the surface area of ​​the radiation source.

[0153] As shown in Figure 2, each optical directing component subtends less than one third of the solid angle through which radiation is emitted by the three-dimensional object. In particular, each optical directing component subtends less than one sixth of the solid angle through which radiation is emitted by the three-dimensional object. In this way, there are six equal-angle optical directing components around the object.

[0154] Thus, in Figures 4A and 5, a method is provided for viewing a three-dimensional object, where the object is moved along a path and illumination radiation is applied to the object as it moves along the path.

[0155] The radiation reflected by the object is collected by a plurality of optical directing components disposed at angularly spaced positions about the path, each optical directing component subtending less than half of the solid angle through which radiation is reflected by the three-dimensional emitter.

[0156] As noted above, each optical directing component subtends less than one-third of the solid angle through which radiation is reflected by the three-dimensional emitter, and typically less than one-sixth of the solid angle of radiation emitted by the object. Thus, there are six equal-angle optical directing components around the path.

[0157] Figure 5 shows a further arrangement similar to Figure 4A for directing radiation onto a singulated object 100 to be observed passing along a tube 101 and collecting reflected and scattered radiation from the object for measurement. In this embodiment, the object is indicated at 100 and is illuminated by three beams 117, 118 and 119 directed radially onto the object. Each beam 117, 118 and 119 is supplied by a respective light guide 111B, 112B and 113B. Each light guide 111B, 112B and 113B carries light from a set of split sources 111A, 112A and 113A, which may correspond for example to the waveguides 411, 412 and 413 of Figure 4. Alternatively, the split sources 111A, 112A and 113A may each be generated by a suitable separate source. Light guides 111B, 112B, and 113B may include collimation lenses at their ends (not shown). The guides are positioned 120 degrees apart around tube 101. The guides may be sheets, with a length along the tube that is greater than the angular dimension. Each beam thereby projects radially inward from the surface of the tube to pass through the axis of the tube where the object is preferentially located. Each beam terminates at a respective beam stop 114, 115, 116 that forms an absorbing material, so that radiation passing through the object to the other side of the tube is absorbed for collection, rather than reflected or scattered. Perfect collimation of beams 117, 118, and 119 is desirable, but is not practical. Optical elements 111B, 112B, and 113B are designed and fabricated to keep the beam divergence below a threshold angle. The threshold angle may be in the range of 3 to 5 degrees, for example. As shown, the beam diverges slightly so that the angles to the stops are greater than the angles to the respective emission guides.

[0158] Light emitted from the object is collected by six collectors 121A-126A which convey the light through a light guide to inputs 121B-126B of a spectrometer 120. The spectrometer may be, for example, the HEMS configuration cited above by the inventor.

[0159] The collectors thus fill the space between the emitter and the respective beam stop, so that light is collected at a full 360 degree circumference away from the emitter and angle relative to the beam stop.

[0160] Figures 6A, 6B and 7 show another configuration for using two parabolic reflectors in a back-to-back array with the source being typically elongated, such as a tube.

[0161] 6A shows an arrangement for collimating and directing radiation from a radially symmetric radiation source, generally designated 200, through an aperture. The radiation source 201 is radially symmetric about an axis 202 and is located at the focal points of parabolic reflectors 211 and 212. The radiation source 201 may be, for example, a cylindrical gas discharge light bulb. The parabolic reflector 211 has an axis 211A perpendicular to the light bulb axis 202. Similarly, the parabolic reflector has a parabolic axis 212A perpendicular to the light bulb axis 202. The parabolic reflectors 211 and 212 intersect at a neck 210, with the respective reflective surfaces extending from the common neck 210 to two separate mouths 211M and 212M, respectively. Neither parabolic reflector has a surface between the parabolic apex and the neck 210. As shown at 205, light rays emitted by the source 201 that intersect the parabolic reflector 211 at any point within the angle 208 between the neck 210 and the mouth 211M are collimated in the general direction of the parabolic axis 211A. Note that the angle 208 extends from a line between the bulb center and the neck to a line between the bulb center and the parabolic mouth 211M. Collimation is perfect only for light rays emitted at a point on a line between the focal point of the parabolic reflector 211 and the intersection point with the parabolic reflector 211. Light rays entering the parabolic reflector 211 from a source point that is not collimated with the focal point are approximately collimated only within a small angular range about the parabolic axis 211A. Light rays emitted in the angular range between the paraboloid axis 211A and a line from the focal point 202 to the mouth 211M, as shown at 209, are incident on an additional lens 213. The lens 213 can be, for example, a cylindrical lens with an optical axis parallel to the paraboloid axis 211A and a height axis parallel to and coextensive with the bulb axis 202. The lens 213 is displaced from the bulb center 202 by the focal length of the lens 213, and as a result collimates the incident light rays that are approximately parallel to the paraboloid axis 211A. Light rays emitted from points along a line from the central axis 202 and the lens 213 within the source 201 are perfectly collimated (for an ideal lens). Light rays emitted from other points within the source 201 that enter the lens 213 are directed within a small angular range close to the paraboloid axis 211A.Half angles 208 and 209 from the paraboloid axis 211A to the neck 210 total 90 degrees, so the paraboloid reflector 211 and lens 213 receive incident radiation emitted primarily in the direction of the paraboloid axis 211A into an angular range of 180 degrees and collimate it into beam 224. By selecting the paraboloid and lens focal lengths for a radially symmetric source 201 radius, the angular divergence of beam 224 can be kept below a selected threshold.

[0162] The configuration of Fig. 6A is symmetrical. The light rays emitted by the source 201 and incident on the parabolic reflector 212 are collimated mainly in the direction of the parabolic axis 212A as beam 225. The light rays emitted by the source 201 and incident on the lens 214 are collimated mainly in the direction of the parabolic axis 212A as beam 225. Thus, radiation collimated in the direction of the parabolic axis 212A is received from an angular range of 180 degrees from the radiation source 201. Thus, substantially all of the radiation emitted by the radiation source 201 is collimated half in the direction of the parabolic axis 211A as beam 224 and half in the direction of the parabolic axis 212A as beam 225. A radiation beam 225 collimated in the direction of the paraboloid axis 212A is reflected by folding mirrors 215 and 216 to form a beam 226 parallel to and laterally displaced from the paraboloid axis 211A. The laterally displaced beams 226 and 224 are combined by lens 217 and focused at focal point 220 onto a source scaled relative to lens 219. The source scaled at 219 is a scaled image of source 201 (and its backside) with a magnification factor M less than 1. Optionally, lens 218 is a cylindrical lens that operates to reduce angular divergence in the direction of source axis 202 perpendicular to the illustrated view. As shown, lens 219 collimates the incident radiation through an opening 221 in wall 223 to form beam 222. The angular divergence of beam 222 increases by 1 / M relative to the angular divergence of the beam incident on lens 217. Therefore, the focal lengths of lenses 217 and 219 are selected to keep the angular divergence of beam 222 below a threshold value.

[0163] Figure 6B shows an arrangement for directing a portion of radiation from a radially symmetric source through multiple apertures 236, 239 and 242. Parabolic reflectors 211 and 212 and lenses 213 and 214 are identical to the arrangement shown in Figure 2A and produce beams 224 and 225. In Figure 6B, beam 224 is focused by lens 231 to form an image for lens 238 at aperture 239 in wall 240. Lens 238 collimates radiation from the image to form beam 241. The focal lengths of lenses 231 and 238 are selected to keep the angular divergence of beam 241 below a threshold. Beam 225 is incident on concave reflector 232, which focuses the incident radiation onto concave reflector 233, which recollimates the radiation with a magnification given by the ratio of the focal lengths of concave reflectors 232 and 233. A portion of the resulting collimated beam is directed through aperture 234 in wall 235 as beam 236. A portion of the resulting collimated beam is incident on optical fiber 237 and transmitted through optical fiber 237 to aperture 242 in wall 235.

[0164] 7 shows the same configuration of back-to-back paraboloids 211 and 212 connected at neck 210 and containing source 202. In this embodiment, radiation from the two paraboloids is directed through apertures 251 and 252, respectively, into reaction chambers 253 and 254 by redirecting the radiation with curved mirrors 256 and 257, respectively, which are shaped as off-axis paraboloid sheets to collimate the light beam focused at the respective apertures.

[0165] In FIG. 7, the lenses 213, 214 are replaced by mirrors 243, 244 shaped as isosceles triangles with the apex angle pointing towards the source. The reflecting triangle 244 blocks the radiation emitted during angle A and reflects it towards the reflecting paraboloid 212. Similarly, the reflecting triangle 243 reflects the radiation towards the reflecting paraboloid 211. Angle A is the angle defined by the respective paraboloid apertures and axis 202. The reflecting triangles are positioned as close as possible to the radiation source 201 so that the radiation reflected towards the paraboloid comes from a point near the radiation source. This minimizes the angular divergence of the radiation collimated by the paraboloid. Empirically, it has been found that a triangle apex angle between 100 degrees and 120 degrees optimizes the proportion of radiation collimated with an angular divergence of less than 13 degrees.

[0166] 6A and 6B thus provide a method for collecting radiation emitted from a radially symmetric radiation source. The method includes providing a first parabolic reflector 211 and a second parabolic reflector 212, each having a reflective surface defining a rear neck 210 and a forwardly projecting mouth 211M and 212M, the first parabolic reflector and the second parabolic reflector configured back to back such that they intersect at the necks and the respective reflective surfaces extend from the respective necks to the respective mouths.

[0167] A radiation source 201 is positioned at the focus of each parabolic reflector, such that radiation emitted from the mouth of each parabolic reflector is collected and radiation emitted by the source in a direction away from the mouth of each reflector 211, 212 enters the other reflector 212, 211 so as to avoid the reflected radiation being absorbed back into the source.

[0168] In FIG. 6B, the radiation from each reflector is collected separately.

[0169] In FIG. 6A, radiation from both reflectors is collocated and transmitted to a common end use point.

[0170] The source and the parabolic reflector are symmetric about the longitudinal axis.

[0171] In each paraboloid, an optical guide member 213, 205 is provided positioned within each paraboloid reflector at a location on its axis spaced from the source so that radiation emitted in a direction beyond the mouth and thus missing the reflecting surface is redirected.

[0172] In Figures 6A and 6B, the optical guide member is a lens that collimates radiation along the axis of a parabolic reflector.

[0173] In FIG. 7, the optical guide member is a mirror that redirects the radiation onto one side or the other of a parabolic reflector.

[0174] In FIG. 6A, the collected radiation is directed into at least one aperture, the area of ​​which is smaller than the surface area of ​​the source.

[0175] In Figures 6B and 7, there are multiple apertures, and the combined area of ​​the apertures is less than the surface area of ​​the radiation source.

[0176] 8 is a schematic cross-sectional view of a method for directing electromagnetic radiation to reactive materials in a reaction chamber. In this embodiment, the chamber may be, for example, a duct through which a fluid is confined, and the electromagnetic radiation may be UVC light, typically of wavelengths between 220 nm and 280 nm, configured to sterilize materials in the fluid.

[0177] This type of configuration is described in detail in the MPS application referenced above, to which reference may be made for further details.

[0178] As described in the above application, by increasing the path length of the electromagnetic radiation through the reaction chamber using multiple reflections from highly reflective surfaces when the amplitude of the electromagnetic radiation exceeds a threshold, the probability of the electromagnetic radiation interacting with the reactive material is increased. The energy density in a volume element of the reaction chamber is obtained by summing the amplitudes of the radiation paths passing through the volume element weighted by their respective path lengths in the volume element. The threshold is selected such that the sum of the amplitudes below the threshold does not modify the total energy density by more than a tolerance value. Empirically, a threshold of 0.01% of the initial electromagnetic radiation amplitude has been found to work well. The probability of interaction is proportional to the energy density of each volume element and thus correlates with the path length of the electromagnetic radiation. Also as described, the reaction chamber 8A includes a pair of opposing reflective surfaces 8B and 8C of the chamber, with at least one, typically both, of each pair of reflective surfaces being concave mirrors. The surfaces 8B and 8C cooperate with a source of radiation 8D or 8E positioned relative to each pair of surfaces to generate electromagnetic radiation that travels between the reflective surfaces in the volume defined by the reflective surfaces. Surfaces 8B and 8C are made smooth and highly reflective so that the amplitude of electromagnetic radiation reflected back and forth between the surfaces remains above a threshold amplitude for at least 10, and preferably more than 100, specular reflections. The path length over which the electromagnetic radiation contributes to the energy density between the surfaces is approximately the distance between surfaces 8B and 8C multiplied by the number of reflections. The source may be positioned on or adjacent to one of the surfaces (8B or 8C), as shown at 8D, or may be located at the focal point of the surfaces, as shown at 8E.

[0179] The reflective surfaces 8B and 8C are spaced apart from one another to define a first side 8F of the volume on one side of the reflective surfaces and a second side 8G of the volume on the opposite side of the reflective surfaces.

[0180] As shown in FIG. 8, in this embodiment, the complete chamber 8A is defined by a number of these chambers 8H, 8I, 8J, 8K, which are defined by stacked pairs so as to be configured side by side. In this way, the side 8G of the chamber 8H coincides with the side of the next adjacent chamber 8I and is open between them, so that radiation escaping through the side 8G of one volume 8H enters the side of the next adjacent volume 8I. This configuration continues through the stack, so that each subchamber connects to the next on its open side. The two ends are closed by reflective closing walls 8L and 8M, so as to form the stack into a closed duct, which is defined by the side surfaces 8L and 8M, as well as by the curved walls 8C, 8D of the stack.

[0181] Thus, the multiple pairs forming the subchambers define a stack of volumes defined by side-by-side subchambers, with radiation being able to pass between each volume and the next adjacent volume.

[0182] It has been found that allowing the radiation to pass to the next volume or sub-chamber allows the radiation to continue to be reflected into that next volume rather than potentially being lost. It has been found that most losses occur at the sides of the volumes, and as a result, recapture of these radiation losses significantly increases the overall efficiency and the number of reflections obtained. It will be appreciated that the increased reflections in each beam increase the magnification effect described in the above-referenced MPS application.

[0183] In FIG. 8, the flow is perpendicular to the sides and is typically directed generally longitudinally of the duct.

[0184] FIG. 8A is an alternative schematic cross-sectional view, similar to FIG. 8, of an alternative configuration for directing radiation into a chamber for fluid flow. In this embodiment, a duct 8N with an inlet end 8P and an outlet end 8Q is shown, and radiation is directed at an angle B with respect to the longitudinal direction of the duct. The duct is formed with a reflecting wall 8R and a transparent portion 8S so that the radiation passes through a window in the side wall of the duct. In this way, the concave reflectors 8B and 8C and the source 8E are positioned outside the duct as separate elements allowing retrofitting to existing ducts. The number of subchambers so formed can of course vary according to the geometry of the system. The sides of the chamber formed by the end subchambers of the stack are not closed by walls in this configuration.

[0185]

[0033] Referring now to Figures 9 and 10, Figure 9 is a cross-section through a portion of the wall of the chamber of Figure 8 or Figure 8A showing that the wall has been coated with a layer of ZrO2 of a thickness selected to produce constructive interference and therefore high reflectance at a given design wavelength, and Figure 10 is a graph showing the effect on reflectance of the configuration of Figure 9 in which the wall is coated with a reflective layer of ZrO2.

[0186] Thus, in this embodiment, a method is provided in which at least one reflective surface 8M of the reaction chamber 8A is formed by a metallic reflective wall, typically aluminum, at least part of which is coated with a layer 8X of ZrO2 (zirconium dioxide) or HfO2 (hafnium dioxide), which have a high refractive index and low absorption of radiation for given wavelengths in the UVC range.

[0187] The layer 8X is applied with thicknesses T1 and T2 selected to increase the reflectivity (by constructive interference) of the radiation at the reflecting surface to a value greater than that of the metal layer alone. As shown, the thicknesses T1, T2 vary at different points on the surface, in particular the thickness varies at different points on the surface as a function of the incidence angle X or Y of the radiation on the surface, so that the thickness is adjusted to optimize the reflectivity via constructive interference at each incidence angle. The constructive interference condition can be met by increasing the incidence angle by decreasing the thickness of the layer which increases the reflectivity over a wide range of wavelengths. The thickness of the layer is preferably increased at the higher incidence angles, which gives a higher reflectivity maximum over a narrower wavelength range centered on the design wavelength. The thickness can vary in steps as shown, but more preferably it is gradually changed depending on the incidence angle of the radiation expected or calculated to strike the point in question. In a preferred embodiment, the thickness increases with the incidence angle up to the maximum value that can be practically obtained. Thus, as shown in FIG. 10, an initial thickness of 44 nm results in a level of reflectivity for radiation with a wavelength of 270 nm. As described in the above-cited MPS application, this level of reflectivity is increased relative to bare aluminum, reducing reflection losses and therefore increasing the number of reflections that occur. Note from the graph that the level of reflectivity decreases for p-polarized radiation as the angle of incidence increases, and as a result the thickness at these angles must be increased to at least 50 nm, and preferably as much as 64 nm. Specifically, the thickness of the ZrO2 layer increases as the angle increases, so that radiation reflected from the ZrO2 surface increasingly interferes with radiation reflected from the aluminum surface at certain angles of incidence.

[0188] However, in some cases, the maximum thickness that can be achieved in practical application methods is limited, and in those situations material is omitted so that the metal wall is bare at angles of incidence greater than a given value. Thus, for example, a layer of ZrO2 may be added to the aluminum surface by reacting ZrF6 with the aluminum surface in the presence of a small amount of water. This process is self-limited to a thickness of about 50 nm. In this case, it is preferable to leave bare the areas of the aluminum surface where the average angle of incidence requires a coating thickness greater than 50 nm.

[0189] The coating of layers also has the advantage that the material provides increased hardness to the metal wall, thus reducing damage from scratches that would reduce specular reflectivity.

[0190] 11, 12 and 13, there is shown an arrangement using the directional decontamination beam of FIG. 3 for decontaminating objects such as vehicle seats between uses by different passengers.

[0191] The vehicle decontamination system 11A shown in Figure 11 includes a directional UV radiation source 11B, for example provided by the structure shown in Figure 3 described above, a control unit 11C and a positioning actuator 11D.

[0192] The control unit 11C includes a processor 11E along with a data store 11F and a communication interface 11G. The control unit data store includes a dose map in the form of a three-dimensional model of the surface locations to be decontaminated, e.g., passenger seats 11X, and a set of properties associated with each location. The stored properties may include information about the surface normal, reflectivity, scattering, and absorptivity as a function of the angle of incidence, and dose sensitivity. For example, a smooth metal surface may require a smaller decontamination dose than a rough cloth surface. The surface properties may include historical information about the probability of contamination. For example, if a person known to be infected with a pathogen has been at the location, the probability of contamination at that location and nearby locations is higher than the average probability of contamination.

[0193] The control unit 11C may be linked to sensors 11H of the source 11B that measure the temperature, pressure, humidity and molecular composition of the fluid (most often air) between the surface location and the directional UV source 11B.

[0194] The surface characteristics associated with the data storage device 11E with each location further include the dose of UV radiation required to achieve a given level of pathogen reduction for each type of pathogen known or expected to be present. For example, the dose required to achieve a log3 reduction for a given pathogen population may differ depending on whether the pathogen is on a metal surface or a fabric surface. The dose requirements stored for each surface type are preferably previously measured directly using calibration samples. Specifically, multiple samples of each surface type are inoculated with a known concentration of pathogens, and then each sample receives a different set of UV doses. The log reduction is then determined by measuring the number of viable pathogens relative to the initial number.

[0195] The characteristics of the location may further include the risk or probability that contamination at the location has been transferred to a second surface of the location by contact. For example, the second surface may be touched by a human hand, with the transfer probability depending on the surface material and the possible contact time. For example, a touch screen may have a high transfer probability, whereas a ceiling that is rarely touched may have a low transfer probability. It is worth noting that small particles are constantly adsorbing and desorbing from surfaces with temperature-dependent residence times. Thus, pathogen particles on a first surface with a low transfer probability may migrate to a surface with a higher transfer probability. The data storage device 11E preferably takes into account the time-dependent probability of transfer in the risk-weighted model.

[0196] Control system 11C can receive pathogen reduction goals from a user at interface 11F and calculates the risk-weighted dose required at each surface location from that goal based on surface characteristics, transmission probability and dose sensitivity to meet the target pathogen reduction. Positioning actuator 11D then positions and orients directional UV radiation source 11B to deliver the required dose to each surface location.

[0197] The source positioning movements may be provided by a human operator who moves and orients the decontamination system in response to commands and feedback from the control system 11C. In this embodiment, the control system 11C may use the sensors 11J1 and 11J2 to determine the position and orientation of the decontamination system (and thus the position and orientation of the directional UV source) and calculate the dose to be delivered to each location to be decontaminated based on the location and orientation of the directional UV source. The control system 11C may generate visual and audio signals to the human operator with information regarding which surfaces have received a sufficient dose and which have not.

[0198] In a preferred embodiment, the positioning actuator 11D is a robot that guides the decontamination system along a controlled path. In this embodiment, the control system 11C further includes a subsystem 11K that measures the position and orientation of the decontamination system, and a subsystem 11M that operates to position the decontamination system by driving a motor that controls the actuator 11D. The positioning subsystem is preferably operable to position and orient the directional UV source in six degrees of freedom (any position and orientation). In some embodiments, a smaller number of degrees of freedom may be used. The control system 11C may calculate multiple decontamination system paths that meet the user-supplied decontamination goals. The control system 11C then selects a path from multiple paths that meet the decontamination goals. The selected path may be, for example, a path that minimizes the time required for decontamination. Alternatively, the path selection algorithm may minimize the energy required for decontamination. The control system 11C then generates a signal to the actuator 11D that causes the decontamination system to move along the selected path.

[0199] Optionally, the decontamination system includes a detector 11N that measures the UV source intensity, and the control system 11C uses the measured source intensity to dynamically adjust the exposure time at each location based on the measured source intensity so that the required dose is delivered to each location. This feature is useful to compensate for the degradation of the radiation source intensity as the radiation source ages. Furthermore, if the measured source intensity falls below a threshold, the control unit 11C can generate a signal to an operator that maintenance (replacement of the source) is required.

[0200] Optionally, the decontamination system includes a detector defined by camera 11H that measures radiation reflected or scattered from a surface location, and control system 11C uses the intensity received at detector 11N along with the surface characteristics of the location to calculate the dose received at the surface location and adjusts exposure time so that the required dose is delivered to each location. As described in more detail below, the wavelength measured by camera 11H may be different from the wavelength of the collimated beam generated by 11B used for decontamination. For example, the camera may measure intensity at visible wavelengths (400 nm to 800 nm), and the decontamination wavelengths may be between 220 nm and 280 nm.

[0201] Optionally, the decontamination further includes a probe 11P for collecting samples from the surface site before or after irradiation, and the collected samples are analyzed for viable pathogens. This feature can be used, for example, to determine whether the dose is sufficient for pathogens actually encountered as opposed to expected pathogens. Note that the type of pathogen may change due to mutation or the emergence of new types. The analysis can be performed by standard wet chemistry methods. The analysis is preferably performed using the rapid methods described by the HEMS patents cited above.

[0202] Optionally, the decontamination system further includes a collecting means 11Q operable to collect particles from the surface of the object 11X. The collecting means 11Q may include an agitator and a collector. The agitator may be a mechanical or pressurized gas stream, and the collector is an aspirator. The agitator operates at the surface location to remove adsorbed particles (including pathogen particles), and the aspirator draws the particles so removed into a stream for processing or measurement. For processing, the stream of removed particles may be directed into a multi-pass photochemical chamber, as disclosed in the above-cited MPS application.

[0203] In some embodiments, the agitator and collector 11Q is configured as described in U.S. Pat. No. 8,345,254, issued Jan. 1, 2013 to Prystupa, Multiple Pass Imaging Spectroscopy, the disclosure of which is incorporated by reference herein or may be referenced in further detail.

[0204] The sample material removed from the surface of the object 11X by the agitator and collector 11Q can be processed and tested for the type and number of microorganisms present by various methods described below. The agitator and collector 11Q can be used to randomly sample locations on the surface of the object 11X, and analysis of the particles collected at the sample locations provides detailed information about the materials and contaminants present at the locations. The spatial distribution of materials and contaminants can be analyzed by the control unit 11C to build a statistical model of the probability of contamination at the locations and to detect systematic problems with the sanitization procedure. This is in a similar manner to how food is statistically sampled to detect hygiene problems in processing protocols and equipment. Information from the randomly sampled locations on the object 11X can be used to build a statistical model that predicts the probability of contamination as a function of location. As described above, the location-dependent probability can be used to optimize the allocation of UVC doses. Allocation optimization refers to allocating finite doses between different locations to minimize the overall number of remaining pathogens or to minimize the probability of transmission of pathogens to humans using location-weighted transmission probability. For example, humans are more likely to interact with a touchscreen than a ceiling, so a greater log reduction in potential pathogens on a touchscreen than on a ceiling will significantly reduce the probability of transmission to humans than if the touchscreen and ceiling were treated with a beam generated by a collimated source 11B that would give an equal log reduction in potential pathogens. In some embodiments, a sample is collected by a collector 11Q from a location prior to sanitization with UVC irradiation by the directional source 11B, and the controller 11C determines the directional UVC dose to be delivered to the location based at least in part on measurements of the sample from the location. For example, the control unit 11C may assign a higher dose of UVC radiation to a first location that has a higher than average measured contamination level (or transmission probability) based on risk, and a lower dose of UVC radiation to a second location that has a lower than average measured contamination level (or transmission probability).For example, the controller 11C can infer the most likely spatial distribution of contamination on the object 11X from a limited set of random locations using methods of compressive imaging known to those skilled in the art. The controller 11C can further determine a risk-weighted dose of UVC radiation from the directional source 11B for locations not directly sampled based at least in part on the most likely spatial distribution of contamination.

[0205] In some embodiments, the probe 11P and / or the agitator and collector 11Q may be used to determine the presence of viable microorganisms at a location after irradiation with the directional UVC source 11 B. In this embodiment, the information may be used to verify and document the effectiveness of the sanitization process.

[0206] The biological sample from the stirrer and collector 11Q may be transported to and deposited on a suitable optical substrate, for example, using a microfluidic system, preferably of the configuration described in PCT Application No. WO2021 / 163799, published by the present inventor on August 26, 2021, and entitled Field Programmable Fluid Array, the disclosure of which is incorporated herein by reference or may be referenced for further details.

[0207] In some embodiments, surface-enhanced Raman and infrared spectra may be collected by placing the biological sample from collector 11Q on a magnetic object, as described in PCT Application No. WO2021 / 163798, published by the present inventor on August 26, 2021, and entitled Magnetic Platform for Sample Orientation.

[0208] The spectrum is preferably measured using a configuration described in the HEMS patents cited above and which provides an excellent signal-to-noise ratio, the disclosures of which are incorporated herein by reference or may be referenced for further details.

[0209] In some embodiments, the biological sample material is arranged in a configuration described in the above-cited multiple-path imaging spectroscopy patents, and optical amplification is used to increase the signal level and reduce the measurement time. In other embodiments, the surface is directly sampled by the probe 11P using an internal reflection configuration described in the above-cited multiple-path imaging spectroscopy patents. The amplified absorption spectrum is preferably measured by the above-cited HEMS method. In some embodiments, the biological material from the collector 11Q is arranged in a configuration described in U.S. Provisional Patent Application No. 63 / 120,318, filed December 2, 2020 by the present inventor and entitled Amplified Multiplex Absorption Spectroscopy. The amplified absorption spectrum is preferably measured by the above-cited HEMS method. In some embodiments, the biological material from the collector 11Q is arranged in a configuration described in U.S. Patent Application No. 17 / 387,553, filed by the present inventor on July 28, 2021, entitled Multi-dimensional Spectroscopy, now published on February 3, 2022 as U.S. Patent Publication No. 2022 / 0034817. The multi-dimensional spectrum is preferably measured by the HEMS method cited above. In some embodiments, the biological material from the collector 11Q is tested for biochemical composition, e.g., DNA or RNA. In this embodiment, the speed of testing may be increased using a configuration described in U.S. Patent Application No. 17 / 387,533, filed by the present inventor on July 28, 2021, entitled Directed Orientation Chemical Kinetics, now published as PCT Publication No. WO 2022 / 020955.The data from the above cited spectral and chemical methods is preferably analyzed to determine the type of microorganisms present by using the methods described in U.S. Provisional Patent Application No. 17 / 535,034, filed by the present inventor on November 24, 2021, entitled Spectral Diagnostic System, and published on June 16, 2022 as U.S. Patent Application Publication No. 2022 / 0170839, the disclosure of which is incorporated herein by reference or may be referenced for further details.

[0210] In some embodiments, the detector 11H is a multispectral imaging camera. The multispectral imaging system is preferably of the configuration described in the above-cited HEMS patent by the present inventor. Other multispectral imaging systems may be used. The multispectral imaging system provides images of the object 11X or a portion thereof for at least three different wavelengths, more preferably more than 100 different wavelengths, and most preferably more than 1000 different wavelengths. In this embodiment, the entire surface of the object 11X may be scanned, and the locations requiring sanitization are determined based at least in part on the spectral profile of each location. The spectrum of each location is found by mapping each location to an area of ​​the spectral image by methods known in the art (comparing measurements from the image and distance sensors to a three-dimensional model of the environment). That is, the spectrum of each location is compared to the spectra in a spectral database, and the composition of the material at each location is determined, at least in part, by the control unit 11C by matching the location spectrum to a combination of one or more known reference spectra. The spatial resolution of the multispectral imaging system 11H is selected to resolve the smallest contaminant particles known or expected to be present. For example, the inventors have determined that a spatial resolution of approximately 0.3 mm is required to detect the presence of fecal contamination on a surface. Controller 11C determines the UVC dose at each location on object 11X based at least in part on the material determined to be present at that location by analysis of the spectrum from that location.

[0211] Thus, the methods herein include collecting a multispectral image of at least a portion of an object, determining at least in part a type of contamination at different locations in the multispectral image by comparing the spectrum of each location to a reference spectrum, and directing a beam to locations in the multispectral image based at least in part on the type of contamination. Each spectrum in the multispectral image is preferably comprised of more than three different wavelengths, although less than three may be used. Each spectrum in the multispectral image is preferably comprised of more than 100 different wavelengths.

[0212] Optionally, the decontamination system includes a position verification system 11J1 as a component of the head 11R on which the source 11B is mounted, which may be a camera operating with software to track the location to which the directional UV source is pointed as a function of time. The position verification means may include a LIDAR unit that measures the distance from the directional UV source to the surface location. The position verification system may include an acoustic unit that measures the distance from the directional UV source to the surface location. The control system 11C may use the time, distance, and location information together with calibration information regarding the spatial distribution of radiation from the radiation source to calculate the dose received (or delivered) by each location.

[0213] In some embodiments, the dose information is displayed on an overlay image to the operator on the interface 11F, the overlay image including an image of the surface to be decontaminated with a suitable color representation of the dose received at each location relative to the required dose at each location. The interface 11F may be, for example, a touch screen or a mobile phone screen, with a data link between the control unit 11C and the display means. For example, locations that have received zero dose may be shaded red, locations that have received an incomplete dose may be shaded yellow, locations that have received the desired dose may be shaded green, and locations that have received an excess dose may be shaded blue. Other shading schemes may be used, and the number of shades may vary to suit the sophistication of the operator. In a preferred embodiment, the location and dose information is stored in a database. The database information may be used to verify that the user-specified decontamination goals described above are met. The database information may be used in combination with the pathogen indicators to adjust the dose.

[0214] Optionally, the decontamination system camera 11H may act for dose monitoring, measuring reflected and scattered radiation from a location to calculate the intensity of radiation received at the location. The reflected and scattered radiation may be the primary decontamination radiation at source 11B at a UV wavelength, or a secondary wavelength radiation from source 11U mixed in a certain ratio with the primary radiation. In some embodiments, a detector such as camera 11H sensitive to the primary UV wavelength measures the intensity of reflected and scattered UV radiation from a location. The control system 11C uses the intensity information together with the (previously measured) bidirectional reflectance function (BDRF) of the location to calculate the intensity received at the location. For example, the previously measured BDRF may indicate that 1% of the radiation received from the source direction is reflected in the direction of detector 11H. In this case, the intensity at the location is calculated as 100 times the intensity received at the detector. In some embodiments, a second wavelength from source 11U is mixed in a fixed ratio with the primary wavelength in the directional UV source, and the second wavelength is measured by a detector such as camera 11H. The second wavelength preferably has similar reflectance and scattering properties as the primary UV wavelength. The secondary wavelength may be, for example, a blue wavelength between 405 nm and 480 nm that is easily measured with a silicon-based photodiode or photodiode array.

[0215] The number of pathogens, N, transmitted from an object, 11X, to a host species, such as humans, is N=ΣA i P i exp{-k i f i t i} It can be calculated as follows.

[0216] In the above formula, A i is the area of ​​the i-th region of the object 11X, and P i is the probability of transmission from the i-th region to the host species, and k i is the effective decay constant of the pathogen in the i-th region, and f i is the radiation flux in the i-th region, and t iis the time that the flux is directed at the i-th region. The sum is over all values ​​of i. The probability of transmission from each region P i may be measured experimentally or inferred from statistical analysis of known transmission cases. i generally varies between different surface materials due to differences in binding energies between the surface and the pathogen, and differences in the pathways from the pathogen retention site to the external host species. For example, a pathogen embedded in a fabric may need to pass through multiple binding sites to reach the host species, whereas a pathogen on a smooth surface may be directly transmitted to the host species by overcoming only one surface binding energy.

[0217] Effective damping constant k i is based on the decay constant k for the pathogen species modified by the environment in region i. The decay constant k has been experimentally measured for standard conditions and reported in the scientific literature for hundreds of pathogen species. The environmental modification from the standard conditions may be due to geometric shading effects, or differences in temperature and humidity. For example, fibers on the fabric surface may absorb radiation and reduce the effective radiation dose at the pathogen. As mentioned above, temperature and humidity may be measured and used to calculate the environmentally modified decay constant.

[0218] One advantage of the present invention is that the flux coefficient f i has minimal spatial variation due to beam collimation and can be approximated as a constant. The dose in each region is then determined by the time t i is proportional to.

[0219] 12 and 13 provide a flow chart describing the above-described operations performed by control system 11C.

[0220] FIG. 14 shows a schematic of an arrangement for sterilizing a water stream, generally shown as the area within the dashed box 14A. The arrangement uses elements of the reaction chamber for sterilization described in the above-cited MPS patent by the present inventor. The water supply is contained in a container 14B. The container 14B may be, for example, a water bottle or storage container of conventional design. The container 14B may be, for example, a water pitcher. The container 14B may be, for example, a water pipe or a water faucet. The container 14B may include integral attachment means, which may be, for example, a threaded portion of a conduit. In other embodiments, the sterilization attachment 14D is a conduit that attaches to the container 14B by a press fit. In other embodiments, the sterilization arrangement 14D may be suspended within the container 14B or attached to the side of the container 14B with a clip. The arrangement 14D may be attached to the water container 14B by a coupler 14C. The coupler 14C may be, for example, a fitting having an internal thread designed and manufactured to mate with an external thread on an integral mounting means of the water container 14B. The coupler may be different for each type of water container 14B, but provide a common interface to the remaining components of the water sterilization device 14D. That is, the device 14D may be adapted to any conventional water container by selecting the appropriate coupler 14C. The coupler 14C communicates with a water filter 14F, which functions to reduce particulate matter and, optionally, to reduce selected chemical contaminants. Water flows from the water container 14B through the coupler 14C and filter 14F into the sterilization chamber 14D. The sterilization chamber 14D includes opposing highly reflective concave mirrors 14G and 14H. The water may flow around the edge of the concave mirror 14G to enter the chamber 14D, as shown at 14E. Similarly, water may flow around the edge of concave mirror 14H toward and through outlet 14T. Thus, water may flow continuously from water reservoir 14B to water outlet 14T. UVC radiation at wavelengths between 200 nm and 290 nm enters sterilization chamber 14D from light source 14L through opening 14A in concave mirror 14H.The path length of UVC radiation above a threshold amplitude in chamber 14D is increased by reflection between concave mirrors 14G and 14H, thereby amplifying the germicidal effect of UVC light entering chamber 14D by at least 10 times, preferably 100 times or more. Amplification is achieved by using highly reflective dielectric mirrors at 14G and 14H and by selecting an appropriate chamber geometry, which is described in more detail in the above-cited MPS patent by the present inventor. Light source 14L may be, for example, an LED connected to power source 14J under the control of control means 14K. Alternatively, light source 14L may be connected to the light source by a waveguide, for example as shown in Figures 2, 3 or 4B. The control means communicates with sensor 14S, which is operable to measure at least one property and optionally multiple properties of the water. The properties may be, for example, flow rate, temperature, turbidity, conductivity, and pH. In one embodiment, the control means may include a user interface that allows a user to manually turn on the germicidal function, control the amplitude of the UVC radiation, and provide function status information. In another embodiment, the control means may automatically activate the UVC light source when water flow is detected.

Claims

1. 1. A method for exposing a reactive material in a reaction chamber to electromagnetic radiation, comprising: introducing the electromagnetic radiation into the reaction chamber; and increasing the probability of the electromagnetic radiation interacting with the reactive material by increasing the path length of the electromagnetic radiation within the reaction chamber using multiple reflections when the amplitude of the electromagnetic radiation is above a threshold value; the reaction chamber includes a plurality of pairs of opposing reflective surfaces in the reaction chamber; at least 50%, more preferably at least 80% or 90% of the reflection from said reflective surface is specular; at least one of the reflective surfaces of each pair is a concave mirror; the reflective surfaces of each pair are configured to cause reflection of the electromagnetic radiation passing between them within a volume defined by the reflective surfaces; the reflective surfaces of each pair are spaced apart to define a first side of the volume on one side of the reflective surface and a second side of the volume on the opposite side of the reflective surface; The method wherein the plurality of pairs are configured side by side such that radiation escaping through the side of one volume enters the side of the next adjacent volume.

2. The method of claim 1 , wherein a plurality of pairs of the reflective surfaces side by side define a stack of the volumes, and the radiation can pass between each volume and the next adjacent volume.

3. The method of claim 2 , wherein an end volume of the volumes has a reflective sidewall on an outer one of its sides.

4. A method according to any one of claims 1 to 3, wherein the reflective surface forms a side wall of a duct.

5. A method described in any one of claims 1 to 3, wherein the flow is perpendicular to the side.

6. The method of any one of claims 1 to 3, wherein the radiation is directed into a duct through which a fluid passes.

7. The method of claim 6 , wherein the radiation is directed generally longitudinally of the duct.

8. The method of claim 6 , wherein the radiation is directed at an angle relative to the longitudinal direction of the duct, and the radiation passes through a window in a sidewall of the duct.

9. The method according to any one of claims 1 to 3, wherein a major part of the radiation path comprises at least 10, preferably more than 100 reflections from surfaces bounding the reaction chamber.

10. 4. The method of claim 1, wherein the reflective surfaces define at least one central optical axis extending therebetween and along which the reflection passes, and wherein the source of radiation is positioned between the reflective surfaces at a position offset from the central optical axis such that a locus of the reflection moves towards the central optical axis.

11. The method according to any one of claims 1 to 3, wherein the source of radiation is positioned on one side of at least one of the reflective surfaces of a reflective pair.

12. 4. The method of claim 1, wherein the reflective surface is a concave mirror, a source of radiation is positioned at a location on at least one of the concave mirrors, and the source of radiation has a dimension that is less than 0.03 times the focal length of the concave mirror.

13. A method according to any one of claims 1 to 3, wherein the source of the radiation source is positioned at the focus of the concave mirror.

14. A method according to any one of claims 1 to 3, wherein the offset between each beam and the next after reflection is less than the width of the beam, so that the beams form a complete curtain.

15. 4. The method of any one of claims 1 to 3, wherein an inlet port for receiving reactants and an outlet port for discharging products are provided, and wherein an absorbing surface is provided that is shaped and configured to stop transmission of electromagnetic radiation from inside the reaction chamber to an exterior location.

16. 16. The method of claim 15, wherein the inlet port and the outlet port are not on an axis of symmetry of the reaction chamber.

17. The method of any one of claims 1 to 3, wherein at least a portion of the chamber wall is diffusely reflective of electromagnetic radiation.

18. The method of any one of claims 1 to 3, wherein the reactive species is entrained in a fluid flow, the fluid being a liquid or a gas.

19. 4. The method of any one of claims 1 to 3, wherein the electromagnetic radiation is UVC radiation and the reactive material is a microorganism selected from the list of bacteria, viruses, protozoa, helminths, yeasts, molds, or fungi, and the UVC radiation inactivates the microorganism.

20. The method of any one of claims 1 to 3, wherein the electromagnetic radiation is at least partially collimated so that it travels primarily back and forth between the reflective surfaces.

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